There's never been a good solution to clearing fogged-up windshields, other than to wait for a car's heater to kick in, then maybe run the air conditioning at the same time for that extra atmospheric shove. But now some researchers at MIT have come up with a coating that could prevent fog — just tiny water droplets that scatter light — from forming in the first place. Like so many other inventions these days, the key discipline that led to the discovery was nanotechnology — the coating comprises nanoparticles of silica, from which glass is made, that creates a porous surface to keep moisture from blocking light. It's actually pretty complex, though the result could make cold mornings less of game of idle ass-freezing.